Obi announced his resignation in a letter dated 20, addressed to the National Chairman of the party.
In the letter sighted by Vanguard, Obi gave reasons for his withdrawal from the presidential race.
The letter said: “I am writing to intimate you of my resignation from the Peoples Democratic Party (PDP), which was conveyed to the Chairman of Agulu Ward 2. Anaocha LGA
“Anambra, effective Friday 20 May, 2022. Consequently, am by this letter informing you of my withdrawal for the PDP Presidential Primaries.
“It has been a great honour to contribute to nation-building efforts through our party. Unfortunately, recent developments within our party make it practically impossible to continue participating and making such constructive contributions.
“Our national challenges are deep-seated and require that we each make profound sacrifices towards rescuing our country. My commitment to rescuing Nigeria remains firm, even if the route differs.
“I wish to thank you personally for your graciousness and leadership. I wish you well and best of luck in the service of country.“